It’s been a few years since Are Your Dog’s Food Bowls Safe? A Pet Bowl Materials Guide was published. Since then, stainless steel products have surged in popularity and can be found in a number of products for both humans and pets. As such, there has been a significant increase in manufacturers of stainless steel items that range from low to high quality. With the EPA awareness now prevalent and a abundance of stainless steel bowls vendors now available, there is a new controversial debate and hot topic going on right now: Can stainless steel bowls contain lead?
The answer, at least from a technical standpoint, is: No, there is no lead used to make stainless steel.
However, there are some considerations on how lead can potentially be in some stainless steel product and how it could affect you and your pets. If you’re not interested in the science, you can skip to the end: lead in stainless steel conclusion. Otherwise, let’s take a look at what exactly stainless steel is and how it differs from ‘regular’ steel.
What is Steel?
Steel, by definition, is primarily composed of iron. Iron is a naturally-occurring metal on earth. It is rarely found on the surface because it oxidizes readily in the presence of oxygen and moisture—becoming iron oxide (also known as rust). Because pure iron is relatively soft, other metals are often added to strengthening it into an ‘alloy’. Steel—which can be 1,000 times harder than pure iron—is made by alloying iron with small amounts of other metals and carbon.
There are two basic types of steel: carbon steel and stainless steel.
Carbon steel is most commonly used to make auto bodies, appliances, and sheet metal (fabrication/panelling). It’s easy to distinguish carbon steel because it turns black over time and easily rust when exposed to air and moisture. Carbon steel is made of iron with 0.1 to 1.2 percent carbon and even less manganese.
The majority of consumer products made from steel, such as cookware, bakeware, and cooking utensils are made from stainless steel. Stainless steel is defined as a steel alloy with a minimum of 11% chromium content by mass. Unlike carbon steel that is susceptible to rusting and turning black, stainless steel has the unique advantage of being able to resist stains and corrosion due to its chromium content.
The chromium provides a layer of chromium oxide over the steel when exposed to oxygen. This layer is impervious to water and air, protecting the metal beneath. When the surface is scratched, the layer quickly reforms itself in a process known as passivation that is often seen in other metals, such as aluminum and titanium. Therefore, when food or water or your body comes in contact with stainless steel, it is actually contacting chromium.
Types of Stainless Steel
Over 70% of stainless steel manufactured is of the 300 series meaning that it has been heated to a temperature high enough to change its crystal structure to a form known as austenite. 300 series stainless must contain a maximum of 0.15% carbon, a minimum of 16% chromium, and sufficient nickel and/or manganese to retain their crystalline structure. These stainless steels are named by their chromium and nickel content. The most common is 18/8 stainless which is defined as a composition of 18% chromium and 8% nickel. 18/0 and 18/10 are also available.
The most common grade is Type 304, which is referred to as A2 or 18/8 stainless steel.
The second most common austenite steel is Type 316 grade, also called marine grade or surgical stainless. In addition to chromium and nickel, Type 316 also contains molybdenum to help maintain a cutting edge and prevent specific forms of corrosion. It is typically used in the manufacturing and handling of pharmaceutical and food products where the minimization of metallic contamination is required.
Type 440 grade is commonly used for make knives due to its increased ability to maintain a sharp edge.
Content of Common Stainless Steels
|SAE||% Cr||% Ni||% C||% Mn||% Si||% P||% S||% N|
|304||18 - 20||8 - 10.5||0.08||2||0.75||0.045||0.03||0.10|
|316||16 - 18||10 - 14.0||0.08||2||0.75||0.045||0.03||0.10|
|440A||16 - 18||-||0.60 - 0.75||1||1||0.040||0.03||-|
|440B||16 - 18||-||0.75 - 0.95||1||1||0.040||0.03||-|
|440C||16 - 18||-||0.95 - 1.20||1||1||0.040||0.03||-|
- Cr (Chromium)
- Ni (Nickel)
- Si (Silicon)
- P (Phosphorus)
- S (Sulphur)
- N (Nitrogen)
Lead in Stainless Steel Conclusion
As you can see, there is no lead used in the production of stainless steel. Even if the product is made in China, there would be no reason why a manufacturer would randomly add lead to the stainless steel formula. Doing so would likely disrupt the stainless steel formulas and it may not set or perform properly. So then…how can some stainless steel products still contain lead?
Based on what I could discover from a few sources including my wife (a chemist), the potential of lead contamination in stainless steel can be due to a few factors:
1. Lead residue. Similar to how some food products has warning labels such as “may contain nuts” or “manufactured in a facility that processes tree nuts” despite not being a nut-based product at all, the stainless steel could have been made in a facility that also make products containing lead. Think of it as lead ‘dust’. The good news is this is a simple fix. Simply thoroughly clean your stainless steel products before use. The lead dust will wash off and your stainless steel products should be fine for use.
2. Not stainless steel. The product in question may not actually be stainless steel but some other type of metal or alloy. The magnet test is not a proper test because the differing amounts of metals in stainless steel can differ and affect its magnetic properties. The best way to test stainless steel requires potentially damaging it: select a spot or item you don’t mind testing and use an eye dropper with muriatic (hydrochloric) acid on it, wait an hour; discoloration and corrosion will occur on stainless steel. As such, the effective solution to this concern may be to focus on obtaining your stainless steel from reputable and proven stainless steel brands and manufacturers.
4. Solder containing lead This typically does not occur in bowls, but many insulated stainless steel bottles use a solder that may contain (but not always) lead to vacuum seal the stainless steel bottle. Most of the time, these spots have a protective cover and is only located on the exterior so it should not affect the interior contents in any way.